Effects of thawing temperature on the physicochemical properties of pre-rigor frozen chicken breast and leg muscles

The objective of this study was to evaluate effects of thawing temperature on the biochemical and physicochemical properties of pre-rigor frozen chicken breast and leg muscles. Breast and leg muscles from 24 broiler chickens were excised within 10 min postmortem. Pre-rigor muscles were frozen at −20 °C and thawed at 0 and 18 °C, and pH, R-value, sarcomere length, muscle shortening, thaw and cook loss, shear force and myofibrillar fragmentation index (MFI) compared with those in pre-rigor or 2 °C chilled muscles. The ultimate pH of 18 °C thawed muscle was lower than that of 0 °C thawed and 2 °C chilled muscles. As expected, the shortening of sarcomere length and muscle length of thaw rigor muscles were more than those of chilled muscle, but there were no significant differences between chilled muscle and 0 °C thawed muscle. Also, there were no significant differences in R-value (Abs 250/Abs 260) and cook loss due to thawing temperature. Samples thawed at 0 °C had higher MFI and lower shear value than samples thawed at 18 °C. Shear force value and MFI were not significantly different between chilled muscle and 0 °C thawed muscle. By thawing at 0 °C, thaw shortening was prevented, and tender meat comparable to the chilled meat was obtained.